The present invention generally relates to the application of indicia to various articles, and in particular, to an apparatus which facilitates the application of indicia to multi-sided articles in a single printing operation.
A variety of articles such as candies, pharmaceutical capsules, tablets and the like, and other pellet shapes, are often marked with identifying indicia. These markings may include various indicia such as trademarks, lot number, manufacturer/company name, etc. A variety of different devices have been developed to accomplish this task.
One device which has found utility in the application of indicia to various pellet shaped articles, especially pharmaceutical tablets, may be found in U.S. Pat. No. 4,308,942, issued Jan. 5, 1982, and entitled "Single Drum Material Orientation Apparatus and Method". This apparatus, which is merely exemplary of this general class of apparatus, makes use of a single rotating drum which is capable of receiving tablets to be imprinted, for orientation and eventual delivery to a conveyor which is capable of drawing the tablets received beneath a printing apparatus. While such devices have proved to be effective in applying indicia to tablets and the like, it has been found that such devices are capable of still further improvement.
For example, it is to be noted that such devices are capable of applying indicia to only one side (or face) of the tablets being processed. Thus, if it becomes necessary to apply indicia to a second face of the tablets being processed, it generally becomes necessary to perform a second, discrete printing operation. This is clearly undesirable in view of cost, and the considerations of time. Moreover, the additional procedures required tend to introduce an additional potential for error into the processing operation, leading to an increase in rejection rate, and accordingly, a decrease in overall efficiency.
Attempts have been made to develop devices which are capable of simultaneously applying indicia to more than one face of a series of articles being processed. An example of one such device may be found in U.S. Pat. No. 3,272,118, entitled "Article Marking Machine". This apparatus incorporates a generally downwardly sloping conveyor for receiving a series of articles from a feed hopper, and for conveying the series of articles received between an opposing pair of printing mechanisms. As the articles are drawn between the opposing pair of printing mechanisms provided, desired indicia are simultaneously applied to each face of the series of articles being processed. However, this apparatus has been found to be less than satisfactory in actual operation.
For example, it will be noted that such an apparatus provides no means for assuring that the articles being processed are appropriately transferred from the feed hopper to the conveyor of the apparatus. For this reason, it is not uncommon for the holders which are drawn through the feed hopper to leave the feed hopper without receiving an article to be imprinted, decreasing the overall efficiency of the apparatus.
Moreover, two-sided printing is accomplished by means of opposed printing mechanisms which must simultaneously contact the series of articles being processed. This presents a significant disadvantage in that proper adjustment of the printing process necessitates a relatively complicated interactive adjustment wherein the location of each printing mechanism is adjusted in relation to the other printing mechanism provided, as well as the series of holders passing between the opposing pair of printing mechanisms.
Also to be considered are the significant difficulties which are encountered when it becomes necessary to change the apparatus over, from the printing of a first type of article to the printing of a second type of article. It will be understood that such a procedure is not possible without dismantling significant portions of the apparatus, to replace the series of holders then in use with a different series of holders adapted to receive the new type of article to be processed. Thereafter, it becomes necessary to readjust the printing mechanisms as previously described. Clearly, these procedures are undersirable, often to the point of precluding the convenient use of such an apparatus to imprint several different types of articles.
It therefore remained desirable to develop an apparatus which is capable of applying indicia to more than one side (or face) of a series of articles, which is convenient to operate, and which does not exhibit the foregoing disadvantages.